For a peace of mind, you might want to consider to overhaul the cooling system. It should be good for the next 5 years or more.
Some reference from a similar S54.
New radiator RM1750
New fan clutch and thermostat approx RM1K for both item. Thermostat shd be approx RM300
Water pump RM1850 with o-ring & gasket
Alternator RM1900
Expansion Tank RM380, coolant RM40
2 bearings, 1 fan belt, 1 aircond belt + labour RM500
Hoses, hoses, etc